title: Clinical correlates of olfactory dysfunction in spinocerebellar ataxia type 3.
abstract: Olfactory dysfunction is a very common and early sign in neurodegenerative disorders, but few data are already available in hereditary ataxias. Our aim was to evaluate the sense of smell in patients with molecular-proven spinocerebellar ataxia type 3 (SCA3). Forty-one patients with SCA3 and 46 control subjects were studied. The sense of smell was tested using the Sniffin's Sticks (SS-16). We also evaluated Mini-Mental State Examination (MMSE) and non-cerebellar symptoms, such as parkinsonism, dystonia, and restless legs syndrome (RLS). The SCA3 group had significantly lower SS-16 scores than controls (11.5 ± 2.4 vs 12.8 ± 1.5, p = 0.003). Multiple linear regression analyses, controlling for age, sex, education, cigarette smoking, and MMSE scores, showed that SCA3 (p = 0.021), sex (p = 0.003) and MMSE scores (p = 0.002) had significant regression coefficients. All the variables taken together were significantly associated with the SS-16 scores (p ≤ 0.001). Although MMSE scores and female sex were stronger predictors of the SS-16 scores than SCA3, subjects with SCA3 had lower scores on the SS-16, regardless of sex or MMSE scores. Additionally, MMSE scores, sex and presence of RLS were the best predictors of SS-16 scores. Overall, our results strengthen that the sense of smell is significantly reduced in patients with SCA3 and that sex, MMSE scores and RLS also influence the SS-16 scores.
authors.affiliation: Department of Neurology and Neurosurgery, Universidade Federal de São Paulo, Brazil. pbraganeto@hotmail.com
authors.forename: P
authors.initials: P
authors.lastname: Braga-Neto
authors.forename: A C
authors.initials: AC
authors.lastname: Felicio
authors.forename: J L
authors.initials: JL
authors.lastname: Pedroso
authors.forename: L A
authors.initials: LA
authors.lastname: Dutra
authors.forename: P H F
authors.initials: PH
authors.lastname: Bertolucci
authors.forename: A A
authors.initials: AA
authors.lastname: Gabbai
authors.forename: O G P
authors.initials: OG
authors.lastname: Barsottini
mesh_terms: D000328:Adult; D005260:Female; D006801:Humans; D017827:Machado-Joseph Disease / Q000150:complications*; D008297:Male; D008609:Mental Status Schedule; D008875:Middle Aged; D000857:Olfaction Disorders / Q000175:diagnosis / Q000209:etiology*; D020187:REM Sleep Behavior Disorder / Q000209:etiology; D012044:Regression Analysis; D012903:Smell / Q000502:physiology*